Many mechanisms are dependent upon the physical positioning of a movable component relative to another fixed, non-movable component of the mechanism. For example, flow control valves are used extensively to control fluid flow in heating and cooling systems used to control thermal loads in, as an example, buildings or other spaces. Performance of the valves, and thus the systems, are typically highly dependent upon the accuracy of identifying and controlling the positioning of the valve member within the housing of the flow control valve. More specifically, pressure independent control valves, such as the DeltaPValve®, manufactured by Flow Control Industries, Inc. of Woodinville, Wash., have been used to provide dramatic improvements in performance of the systems. Such pressure independent control valves are disclosed in, as an example, U.S. Pat. Nos. 4,893,649, 5,143,116, 7,128,086, and other patents issued to inventor Paul Skoglund, all of which are incorporated herein by reference thereto. These valves typically have a valve stem rotatable about an axis of rotation to control the valve position and the associated flow of fluid through the valve. In many applications it can be very advantageous to determine, monitor and control the rotational position of the valve stem and associated valve position. Conventional position detection systems are connected to the top of the valve stem in an axial aligned orientation so as to engage and measure the rotational movement of the valve stem. These position detection systems atop the valve stem typically have accuracy limitations, and many valve installations are not conducive to an axially aligned detection system connected to the top of the valve stem. There is a need for improved control and accurate monitoring of the valves, which can be used to further improve performance of the systems in which the valves are installed.